Negative Colonoscopy Predicts Reduced Risk of Colon Cancer for 17 Years

Douglas K. Rex, MD, MASGE reviewing Pilonis ND, et al. Ann Intern Med 2020 May 26.

Previous studies in symptomatic populations have found that a negative colonoscopy predicts a reduction in colorectal cancer (CRC) incidence for greater than 20 years. The current study examined the impact of a negative colonoscopy in a screening population in Poland, specifically the effects of a high-quality examination (examination to the cecum, adequate bowel preparation, and performance by an endoscopist with an adenoma detection rate [ADR] >20%).

Overall, 165,887 individuals were followed for up to 17.4 years and found to have reductions in CRC incidence and mortality of 72% and 81%, respectively, compared to the general population. The benefits were similar in men and women and seen in both the proximal and distal colon. Beyond 10 years of follow-up, the overall incidence reduction was 69% and mortality reduction was 73%. Compared with low-quality colonoscopy, high-quality examination was associated with a 2-fold greater reduction in the risk for proximal colon cancer. In multivariate analysis, CRC risk was significantly lower among patients who had high-quality colonoscopy than those who had low-quality colonoscopy.


This study is yet another mandate for measurement of ADR and once again proves that high-quality colonoscopies are associated with greater reductions in colorectal cancer incidence and mortality compared to low-quality examinations. These data suggest that in systems where colonoscopy quality is measured and ensured, we could now consider 15-year intervals (and perhaps 20 years) between negative colonoscopies. Expansion of CRC screening intervals would be a major breakthrough in CRC prevention, cost-effectiveness, and the long-term attractiveness of colonoscopy as a screening test.

Douglas K. Rex, MD, MASGE

Bio and Disclosures


Pilonis ND, Bugajski M, Wieszczy P, et al. Long-term colorectal cancer incidence and mortality after a single negative screening colonoscopy. Ann Intern Med 2020 May 26. (Epub ahead of print) (